Solvent for pyroxylin bodies



' siding at Athol, county of Worcester, and- ROWLAND BRITTAIN MITCHELL, 0F ATHOL, MASSACHUSETT S, ASSIGNOR TO ATHOL MANUFACTURING COMPANY, OF AT'HOL, MASSACHUSETTS, A CORPORATION OF- MASSACHUSETTS;

' SOLVENT FOR PYROXYLIN BODIES.

1,398,239, Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, ROWLAND BRITTAIN MITCHELL, a citizen of the United States, re-

State of Massachusetts, have invented a new and useful Improvement in Solvents for Pyroxylin Bodies, of which the following is a full, clear, and exact description.

The object of my invention is to provide a solvent for pyroxylin bodies that will be powerful, complete, and commercially practical and possess the capacity of depositing.

an odorless, tough, homogeneous and nonhygroscopic film of pyroxylin free from bubbles.

A further object is to provide a pyroxylin solvent in which one of the active ingredients is a solid which will remain in the deposited film after the other liquid ingredients have evaporated, thereby imparting greater toughness and also a certain plia- -bility' to the film.

A further object is to provide a pyroxylin solvent of such a nature that certain softening agents,such as castor or rapeseed oil, and certain coloring matters, such as drop black and zinc oxid,"can be added to the pyroxylinsolution without in any way destroyingI its usefulness.

. aturally, a solvent possessing the above qualities would fill asdemand in the pyroxylin industries, such as in the manufacture of artificial leather, lacquers, varnishes and the like. None of the solvents now in use at the present time possesses all of the above qualities. For instance, a well known commercial solvent mixture consisting of ethyl acetate and benzol, toluol or benzin, is apt in humid weather-to deposit a hygroscopic film of nitrocellulose. This hygroscopic quality is very objectionable and is evidenced by a whitish appearance in the film, which is caused by the nitrocellulose being precipitated from solution by the water which .is deposited .on the surface of the film due to the rapid cooling efi'ect of the evaporation of the solvents. The films deposited by various well known solvent mixtures are also apt to contain bubbles or pin holes, which are particul rly obstructive to the production of a sat1 factory piece of artificial leather.- For economy it is customary to add cheap diluents to solvents so as to attenuate their solvent power over the greatest possible amount of nitrocellulose.

Application filed September 22, 1920. Serial No. 411,960.

For instance,- in some lacquer work, a solupyroxylin to the gallon of solvent will produce a satisfactory film, whereas in some Patented Nov. 29, 1921.

.tion containing as little as four ounces ofsolvents. However, as a general rule, the p more diluent added, the less the solvent power of the resultant solution and the more liabilityto blushing of the deposited film.

Amyl acetate possesses desirable qualities as" a solvent, but on account of its hlgh cost is commercially impractical;

In the past it has been customary to use liquid solvents only, where a solution of more or less fluidity has been desired.

I have discovered that it is possible to impart great solvent power to a mixture of alcohol (either methyl, ethyl, or butyl) and benzol- (or toluol or xylol) by the addition of a relatively small quantity of acetanilid and some other solvent such as acetone,- ethyl acetate, methyl acetate, or ethyl propionate. A solvent mixture composed of the above mentioned ingredients not only possesses remarkable solvent power andcheapness, but a pyroxylin solution obtained by using this solvent mixture deposits a film which is nonhygroscopic, odorless, and free from bub bles or pinholes. Acetanilid, having a boilfact also enables the solution to stand a" larger quantity of water without precipitating the cellulose.

My solvent mixture is commercially, practicable because of the ease of manipulation benzol or equivalent diluent which can be used with it.

The pyroxylin solution made from n solvent mixture possesses a texture .whic enables it to be painted or spread very smoothly without the bubbles or pinholes and cheapness due to the large percentage of usually encountered- This'is brought about by the degree to which the solution 1s carried come very cohesive and enabling it to be spread or painted evenly.

The following is an example of a solvent mixture embodying my invention:

Benzol 7 2 parts by weight.- Alcohol 20 Acetone 6 Acetanilid 2 The above is typical formula only, the.invention not being confined to the specific ingreidients or the particular proportions speci- Increasing the amount of acetanilid will result in increased solvent power.

. While I mention acetone specifically, I find that other solvents, such as amyl acetate, ethyl acetate, methyl acetone, methyl acetate, acetone oil, ethyl propionate, ethyl butyrate and methyl butyrate, may be used equally well with the otherthree ingredients without materially changing the properties of the resultant solvent mixtures. v

In place of benzol any of the other low boiling homologues of the benzene series may be used, astoluol or xylol. I

Man other of the aliphatic alcohols may be use instead of ethyl, alcohol and the term alcohol therefore includes methyl, ethyl, butyl, propyl, amyl, etc.

While I prefer to use the four ingredients Specified in the illustrative composition or their descrlbed equivalents, my invention.

does not require their employment in the proportions recited; nor does it exclude the addition of other ingredients; nor is it essential to use all the ingredients- (or their equivalents) specified to secure results approximating'those obtained by the use of the preferred composition. any diluent or diluents, or any ingredient or ingredients functioning mainly as a diluent, may be employed with a plurality of solvents, one of which is acetanilid and the other of which is a solvent boiling at arelatively low temperature. For acetanilid may be substituted any ingredients that is a good sol- 7 less, non-hygroscopic film.

For example,

vent of pyroxylin, that has a high boiling point, that will remain on the deposited film after the other ingredients have evaporated and that will effect the deposition of an odor- Having now fully described my invention, what I claim and desire to protect by Letters Patent is 1. A pyroxylin solvent mixture containing a preponderating proportion of an ingredient functioning mainly as a diluent, and a plurality of ingredients, functioning chiefly as solvents, one'of whch is acetanilid.

2. A pyroxylin solvent mixture containing a preponderating proportion of an ingredient, functioning mainly as a diluent, and relatively small proportions of two pyroxylin solvents, one of. which has a relatively low boiling point and the other of Which has 'a relatively high boiling point and will remain in the deposited film' after the other ingredients have evaporated.

3. A pyroxylin solvent mixture containing a preponderating proportion of an ingredient functioning mainly as a diluent, a relatively small proportion of an aliphatic alcohol, and a still smaller proportion of a plurality of solvents one of which is acetanilid. 1'. A pyroxylin solvent mixture containing a material which is a goodsolvent of pyroxylin, alcohol, a lower member ofthe benzene series of hydrocarbons, and acetanilid.

5. A pyroxylin solvent mixture containing alcohol, a material which is a' solvent of pyroxylin in a proportion substantially less than the proportion of alcohol, acetanilid in a proportion substantially less than the proportion of alcohol, and a diluent in a proportion. substantially in excess of all the other ingredients combined. y I 6. A pyroxylin solvent mixture containing acetone, an aliphatic alcohol, a lower member of the benzene series of hydrocarbons and acetanilid.

In testimony of which invention, I have A hereunto set my hand, at Athol, Mass, on this 16 day of August, 1920.

ROWLAND BRl'l'TAlN MITCHELL. A 

